Prevalence and predisposing factors of aflatoxin contamination in exotic and local eggs sold in shops across Kawempe Division, Kampala, Uganda

Abstract

Aflatoxins are toxic mycotoxins produced mainly by Aspergillus species and are important food-safety hazards because of their carcinogenic and other adverse health effects. Eggs are widely consumed as an affordable source of animal protein, yet limited information exists on aflatoxin contamination of eggs sold in urban retail markets in Uganda. This study determined the prevalence of aflatoxin contamination and assessed selected predisposing factors associated with contamination of local and exotic eggs sold in shops across Kawempe Division, Kampala, Uganda. A cross-sectional study was conducted using 60 egg samples, comprising 30 local and 30 exotic eggs, collected from shops in Bwaise, Kikoni and Kalerwe markets. Thirty egg retailers were also interviewed using structured questionnaires to obtain information on socio-demographic characteristics, sourcing, storage and handling practices. Aflatoxins were extracted using 70% methanol and detected by thin-layer chromatography under ultraviolet light at 366 nm. Data were analysed using SPSS, and chi-square tests were used to determine associations between selected predisposing factors and aflatoxin contamination at a significance level of p < 0.05. Aflatoxin contamination was detected in 11 (18.3%) of the 60 samples. Local eggs had a higher prevalence of contamination (7/30, 23.3%) than exotic eggs (4/30, 13.3%), although egg type was not significantly associated with contamination (χ² = 1.176, p = 0.278). Most assessed factors, including egg source, storage duration, storage method, inspection for spoilage, storage-area hygiene, reuse of trays, separation of damaged eggs, stock rotation and procurement records, were not significantly associated with contamination. However, mould or dampness in the storage area was significantly associated with aflatoxin contamination (χ² = 4.516, p = 0.034), while exposure to heat or direct sunlight showed a relatively stronger but non-significant association (X² = 2.986, p = 0.084). The study concludes that aflatoxin contamination occurs in both local and exotic eggs sold in Kawempe Division, with mould or dampness in storage areas representing an important associated factor. The findings support strengthened food-safety surveillance, improved storage conditions and retailer education, alongside further studies using larger samples, quantitative aflatoxin analysis and assessment of contamination in poultry feeds to clarify contamination pathways and potential consumer exposure.